Circular Segment Calculator

Circular Segment Calculator is the fastest way to solve any circular segment - enter just two values and instantly get all six properties: radius, central angle, arc length, chord length, segment height, and area.
Whether you're a student, engineer, architect, woodworker, or CNC machinist, this calculator handles the geometry so you don't have to.

TWO FLEXIBLE INPUT MODES
Angle & Radius - Know the circle's radius and the central angle? Every other property is solved instantly.
Chord & Height - Working from a physical measurement? Enter the chord length and segment height (sagitta) to back-calculate the radius, angle, and everything else.

WHAT YOU GET
Arc length - exact curved distance along the segment
Chord length - straight-line distance between the two endpoints
Segment height - the sagitta, from chord midpoint to arc
Central angle - in degrees or radians, your choice
Radius - recovered from any two known values
Segment area - precise enclosed area calculation


BUILT FOR REAL WORK
• Real-time results — calculations update as you type, no submit button needed
• Step-by-step explanations — every formula shown with your actual numbers
• Tap to copy — tap any result row to copy the value instantly to clipboard
• Unit flexibility — switch between cm, m, inches, and feet; degrees or radians
• Visual diagram — live canvas updates as you enter values, labeled with r, θ, c, h, and L
• Reference sheet — full formula reference with annotated diagram, always one tap away
• Dark Mode — full system dark and light mode support

WHO USES THIS
Students working through geometry, trigonometry, or engineering coursework
Engineers & architects calculating curved structural elements, arches, and vaults
Woodworkers & makers laying out curved cuts, jigs, and templates
CNC & CAM operators computing toolpaths for circular profiles
Surveyors working with circular curves and road alignment
Anyone who needs quick, reliable circular segment math on the go

Circular segment - is an area of a circle which is "cut off" from the rest of the circle by a secant (chord).

A circular sector or circle sector, is the portion of a disk enclosed by two radii and an arc, where the smaller area is known as the minor sector and the larger being the major sector. In the diagram, θ is the central angle in radians, r the radius of the circle, and L is the arc length of